Investigation of the response of high-bandwidth MOX sensors to gas plumes for application on a mobile robot in hazardous environments

Vincent, Timothy A.; Xing, Yanpeng; Cole, Marina; Gardner, Julian W.

doi:10.1016/j.snb.2018.08.125

Cited by 20 publications

(16 citation statements)

References 19 publications

(21 reference statements)

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“…However, in many applications even lower power consumption is desired, particularly for battery-operated systems. For example, recent mobile platforms integrated MOX gas sensors to patrol hazardous environments for gas leak detection [5], [6]. These platforms operated the gas sensors at a constant temperature, and the power consumption of each sensor was in the order of magnitude of 100 mW.…”

Section: Introductionmentioning

confidence: 99%

“…Nevertheless, such PTO strategies, that successfully save power to the sensing system, come at the cost of sensor performance [12]. For example, faster response times are found at higher operating temperatures [5]. This is because immediately after turning ON the heater, the MOX sensor enters an unstable state characterized by a steady increase of the sensor resistance, also referred to as ''initial action''.…”

Section: Introductionmentioning

confidence: 99%

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Pulsed-Temperature Metal Oxide Gas Sensors for Microwatt Power Consumption

Palacio

Fonollosa²,

Burgués

et al. 2020

IEEE Access

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Metal Oxide (MOX) gas sensors rely on chemical reactions that occur efficiently at high temperatures, resulting in too-demanding power requirements for certain applications. Operating the sensor under a Pulsed-Temperature Operation (PTO), by which the sensor heater is switched ON and OFF periodically, is a common practice to reduce the power consumption. However, the sensor performance is degraded as the OFF periods become larger. Other research works studied, generally, PTO schemes applying waveforms to the heater with time periods of seconds and duty cycles above 20%. Here, instead, we explore the behaviour of PTO sensors working under aggressive schemes, reaching power savings of 99% and beyond with respect to continuous heater stimulation. Using sensor sensitivity and the limit of detection, we evaluated four Ultra Low Power (ULP) sensors under different PTO schemes exposed to ammonia, ethylene, and acetaldehyde. Results show that it is possible to operate the sensors with total power consumption in the range of microwatts. Despite the aggressive power reduction, sensor sensitivity suffers only a moderate decline and the limit of detection may degrade up to a factor five. This is, however, gas-dependent and should be explored on a case-by-case basis since, for example, the same degradation has not been observed for ammonia. Finally, the run-in time, i.e., the time required to get a stable response immediately after switching on the sensor, increases when reducing the power consumption, from 10 minutes to values in the range of 10-20 hours for power consumptions smaller than 200 microwatts.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pulsed-Temperature Metal Oxide Gas Sensors for Microwatt Power Consumption

Palacio

Fonollosa²,

Burgués

et al. 2020

IEEE Access

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show abstract

“…This output can then be used just by itself for fast sensors response, or to replace the raw signal data presented in [ 14 ] for a more accurate gas mapping. This unit was also presented in a previously published paper where the ‘static’ mode of the sensors was used in a customized wind tunnel for plumes investigation [ 15 ].…”

Section: Introductionmentioning

confidence: 99%

Real-Time Thermal Modulation of High Bandwidth MOX Gas Sensors for Mobile Robot Applications

Xing

Vincent

Cole

et al. 2019

Sensors

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A new signal processing technique has been developed for resistive metal oxide (MOX) gas sensors to enable high-bandwidth measurements and enhanced selectivity at PPM levels (<5 PPM VOCs). An embedded micro-heater is thermally pulsed from a temperature of 225 to 350 °C, which enables the chemical reaction kinetics of the sensing film to be extracted using a fast Fourier transform. Signal processing is performed in real-time using a low-cost microcontroller integrated into a sensor module. Three sensors, coated with SnO2, WO3 and NiO respectively, were operated and processed at the same time. This approach enables the removal of long-term baseline drift and is more resilient to changes in ambient temperature. It also greatly reduced the measurement time from ~10 s to 2 s or less. Bench-top experimental results are presented for 0 to 200 ppm of acetone, and 0 ppm to 500 ppm of ethanol. Our results demonstrate our sensor system can be used on a mobile robot for real-time gas sensing.

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“…So far numerous fire detectors based on the detection of gas, smoke, temperature, flame, etc., have been developed (Han and Lee, 2009;Verstockt et al, 2010). Gases or chemical vapors due to pyrolysis or smoldering of the combustible materials are usually emitted before the other fire characteristics become evident, such as smoke and temperature change, and could thus be used as a signature of fire (Fonollosa et al, 2018;Vincent et al, 2019). For many conventional fires, CO has been recognized as the signature gas, which has led to successful application of CO gas sensors in commercial fire detectors.…”

Section: Introductionmentioning

confidence: 99%

Detection of Semi-volatile Plasticizers as a Signature of Early Electrical Fire

Jia

Chen

et al. 2019

Front. Mater.

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Detection of characteristic species released from overheated PVC cables may enable early warning of electrical fire. This work identified the major volatile species for overheated PVC cables, and verified their potential as fire signatures with metal oxide gas sensors. Semi-volatile Dioctyl phthalate (DOP) and 2-Ethylhexanol (2-EH) were found to be ubiquitously present in the cable vapors as major species. Detection of these species and the vapors of overheated cables was accomplished with a metal oxide gas sensor. The response of the gas sensor to the cable vapors resulted mainly from DOP and 2-EH, demonstrating them as effective signature gases for overheated PVC cables. A gas sensor based on SnO 2 nanofibers was prepared with greatly enhanced response to the signature gases. Large-scale simulation tests showed that the nanofiber gas sensor could effectively detect the cable overheating at an early stage.

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Investigation of the response of high-bandwidth MOX sensors to gas plumes for application on a mobile robot in hazardous environments

Cited by 20 publications

References 19 publications

Pulsed-Temperature Metal Oxide Gas Sensors for Microwatt Power Consumption

Pulsed-Temperature Metal Oxide Gas Sensors for Microwatt Power Consumption

Real-Time Thermal Modulation of High Bandwidth MOX Gas Sensors for Mobile Robot Applications

Detection of Semi-volatile Plasticizers as a Signature of Early Electrical Fire

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